1. Field of the Invention
This invention relates generally to electromagnetic shielding, and more specifically to an electromagnetically shielded enclosure having a double perimeter entry seal.
2. Description of Related Art
As the proliferation of radiofrequency generating devices continues at a rapid pace, there is an ongoing and growing need to shield from unwanted electromagnetic radiation for various purposes. For example, certain electronic equipment requires an electromagnetically “quiet” environment to function properly. Such equipment includes, for example, some medical diagnostic and imaging equipment. In addition, testing of electronic equipment often requires a similar electromagnetically “quiet” environment.
In some situations, there is also the need to prevent radiofrequencies from leaving a confined physical area. Such situations include, for example, the use of computer and military electronics where there is the risk of unwanted detection, of a radiated radiofrequency signal or unwanted detection, of the associated harmonics and signature of radiofrequency activity.
Further, testing such as EMI/EMC testing requires the monitoring of electromagnetic energy released from a device under test in a controlled environment where there are little or no outside sources of electromagnetic radiation that could interfere with the monitoring of the device under test. Such testing may also include subjecting a device under test to external electromagnetic energy and monitoring the impact of this external electromagnetic energy on the proper functioning of the device under test.
With the various requirements for electromagnetically shielded enclosures, there exists a need to make these enclosures portable. Lightweight, rapidly deplorable, temporary, and relatively low cost. With the advent of metalized fabrics and textiles, shielded tents and portable enclosures are available today. These enclosures are essentially a Faraday Cage where electromagnetic signals should not pass. Such enclosures come in many shapes and sizes, and are available from various manufacturers. While such enclosures are available, their shielding effectiveness may not always be adequate due to radiofrequency leakage at seams and ingress/egress points such as doors. As such, the overall construction of a portable electromagnetically shielded, enclosure is a vital part of the performance of the shielded enclosure.
The shielding effectiveness of a portable electromagnetic enclosure is controlled by several variables, including the type of metalized fabric used and the overall construct of the portable electromagnetic enclosure. Stitching, fasteners, ventilation, and ingress/egress panels all must be properly designed to limit the amount of electromagnetic leakage. Most portable electromagnetic enclosures have an ingress/egress section such as a door or removable panel. Such doors and panels are prone to electromagnetic leakage, particularly where the door or panel meets the side of the electromagnetic enclosure.
It is thus an object of the present invention to provide an electromagnetic enclosure that is portable, lightweight, rapidly deployable, temporary, and relatively low cost. It is another object of the present invention to provide an electromagnetic enclosure with an entry seal that is not prone to electromagnetic leakage, it is another object of the present invention to provide an entry seal for an electromagnetic enclosure that has a double perimeter seal that is not prone to electromagnetic leakage. It is another object of the present invention to provide an electromagnetic enclosure that is portable and easily adjustable.